Electric-arc lamp



(No Model.)

J. R. POX. ELEGTRIO ARC LAMP.

No. 404,351. Patented May 28, 1889.

\bQr

W'ISW'E SSE S 1N YEN T OR N. PETERS. PhowLiihogrlpMr, Wuhington, u a

UNITED STATES PATENT OEEIcE.

JOHN ROBERT FOX, OF FORT IVAYNE, IN DIANA.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 404,351, dated May 28, 1889.

Application filed August 18, 1888. Serial No. 283,077. (No model.)

To all whom it may concern:

Be itknown thatI, JOHN ROBERT FOX, a citizen of the United States, residing at Fort IVayne, in the county of Allen and State of Indiana, have invented certain new and useful Improvements in Electric-Arc Lamps; and I do declare the following to be afull, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference bein had to the accompanying drawin and to the letters and figures of reference marked thereon, which form a part of this specification.

This invention relates to electric-arc lamps, and has for its object the production of a lamp in which there may be as few parts as possible, with a view to simplifying the structure and reducing the total weight. The are lamps now on the market have considerable weight, a Brush lamp weighing about thirty pounds, a 'Ihomson-IIouston lamp twenty-eight pounds, while the lamp made in accordance with my invention weighs only ten and three-fourths pounds.

A further object of the invention is to insure accuracy in the feeding of the carbon and cut out the lamp at any time when a breakage of the carbons might tend to rupture the circuit.

To these ends my invention consists in a lamp provided with certain structural fea-' tures, which will hereinafter be fully described in this specification, and then definitely indicated in the appended claims.

In another application, filed by me December 31, 1886, I have described an arc lamp embodying certain features of novelty therein claimed. My present application diifers from said prior application in several important particulars, as follows: the manner of fastening together the main and shunt spools, the adjustable stop for determining the length of the arc and limiting the upward movement of the work, the structure of the clutch and the device for releasing it, and the counter-balance for the carbon rod, yoke, and magnetcore.

In the accompanying drawings, which illustrate my invention, Figure 1 is a sectional view of a lamp, the plane of section passing vertically through the regulatingcoils, the circnit-connections bein shown diagrammatically. Fig. 2 is a side view of the lamp with a part of the frame cut away. Fig. 3 is ascetional plan of the lamp on the line :0 1 of Fig. 1.

c is a yoke-frame, into the top and bottom of which are screwed spools a and h, on which are wound the main and shunt coils, respect ively. The coils act as solenoids upon cylindrical iron cores in 92. These cores are attached to a yoke, (Z, in any suitable way. The positive carbon rod 2) extends through the hollow cores within the solenoids and through the yoke. On the upper horizontal side of the yoke (Z is an adj listing-screw, Z, by which the yoke (I may be arrested at any de sired point in its upward travel between the upper and lower interior faces of the yokeframe 0. The yoke-frame c is provided with a slot in its side, through which projects an arm, (1', rigidly secured to the yoke-piece (Z. In this arm and in metallic connection therewith is an adjusting-screw, g, and in the same vertical plane with the said adj Listing-screw is a bindingpost, 71, secured to the yoke-frame 0, but insulated therefrom.

The clutch is composed of two sections, 6 c, which embrace the carbon rod. These sections are pivotally connected on a line below he center, as indicated in the drawings. The arm 6 of the clutch is provided with a tongue, which rests in a slot in. the side of the yoke (1. One section, 6, of the clutch is, as stated, pivotally secured to the section 6, and is held in place by set-screws at the side, as indicated in Fig. 3. This sectional structure causes the clutch to take a quick firm grip on the carbon red when the main coil lifts the yoke (Z. The opening made by the two sections made to flare slightly toward the bottom, as indicated by dotted lines in Fig. 1.

On the side of the yoke-fran1e is pivotally hung a trip-lever, f, which projects inwardly, so that its end lies in the path of the section 6 of the clutch. An adjusting-screw, 7;, is supported in an extension of the yoke-frame and co-operates with a projecting end of the trip-lever, so as to cause it to engage the clutch at any desired point of its downward travel. As the carbon is burned away, an increased flow of current through the shunt-coil draws its core and the yoke with it downwardly, and this operation will continue until the end of the clutch comes into engagement with the trip lever. The clutch end is then held against further downward movement, while its other end is carried lower. This releases the hold on the carbon rod and the latter feeds down to the proper length of arc. The shuntcoil is then short-circuited, and the whole body of the current passing through the main coil stops the carbon at its proper distance of are. To reduce the attractive effort necessary to lift the carbon to a minimum, I pro vide a counter-balance, q, supported adjustably on an arm, 1', pivoted in projections on the side of the yoke-frame (Z. The amount of the counter-balance maybe varied by screwing the Weight q inwardly or outwardly on the arm 0".

The advantage resulting from the use of the rod 3 is that the counter-balance exerts substantially the same amount of lift on the carbon at all points of its travel, whereas, if the inward end of the arm 1" were engaged directly by the yoke, the counterbalaneing effect would vary widely. Another advantage is that the amount of friction is reduced between the yoke and the counterbalance-arm.

The circuits through the lamp in operation are as follows: Entering at the positive side, the current proceeds through the yoke-frame c to the positive carbon, to the negative carbon, thence in the directions indicated by the arrows to and through the main coil and out. The upper solenoid, being thus energized, lifts its cylindrical core, and the yoke, clutch, and carbon with it, and establishes an are between the two carbons. As the main coil is in the are branch, this will force current through the shunt-coil from the positive side of the circuit in the directions indicated by the arrows. The lower solenoid, being thus energized, pulls downwardly on its core and opposes the action of the upper solenoid. The yoke then assumes a position determined by the relative strengths of the two opposing efforts, and would remain fixed if the carbons were not consumed. As the upper carbon is consumed, however, the are lengthens and its resistance increases, thus shunting more cur rent through the lower solenoid and pulling the yoke to alower position. This operation continues until the-clutch engages the triplever and releases the carbon. An establishment of the are then takes place in the same way as before, the clutch taking a new hold on the carbon. The counter-balance permits the use of a' much smaller main coil, and therefore makes a material reduction in the weight of the lamp. If either coil should be injured, its removal and the replacement of a new coil is simply effected by unscrewing the bobbin, unwinding the old, and substituting new wire therefor. If the carbon should from any cause fail to feed,the shuntcoil will continue to pull it down until the screw g strikes the insulated screw h, and by so doing establishes a short circuit for the current from the frame of the lamp through screw h by way of the arrow at the extreme left of .Fig. 1 to the outgoing wire.

Having thus described my invention, whatI claim as new, and desire ,to secure by Letters Patent, isg 1. In an arc lamp, the G01Ilbi112ttiOD,With a central frame, of regulating-solenoids detachably secured thereto, hollow cores controlled by the solenoids, a positive carbon rod extending through the cores, and a clutch controlled by the cores, said clutch engaging the carbon rod.

2. In an arc lamp, the combination of an upper and lower regulating-coil, hollow cores rigidly connected corresponding to the coils, a clutch connecting the positive carbon rod mechanically with the cores, and an adj ustingscreW to limit the upward thrust of the cores and the consequent length of the are.

3. In an arc lamp, the combination, with the regulating-coils, of a vertically-movable frame controlled thereby, a clutch, a positive carbon engaged thereby, one end of the clutch being seated loosely in the frame to permit slight vertical and lateral movement, and a tripping device for engaging the other end of the clutch when it reaches a predetermined limit of depression.

4. In an arc lamp, the combination, with the regulating-coils, of a movable frame controlled thereby, and a clutch supported by the frame, one end of the clutch being provided with a tongue entering a recess in the frame and. the other end engaging the positive carbon rod.

5. In an arc lamp, the combination, with the movable carbon rod, of a counter-balance therefor, comprising a weighted horizontal arm pivotally secured to the frame and a vertical rod pivoted to one end of the arm and bearing against the upper magnet-core.

6. In an arc lamp, the combination, with the main and shunt solenoids secured to a central frame, a movable yoke within the frame, solenoid-cores secured to the yoke, a trip-lever, f, supported on the frame and cooperating with the clutch, and an adjustingscrew, Z, for varying the length of the are, substantially as and for the purpose set forth.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN ROBERT FOX.

WVitnesses:

JULIUs J. EME, N. C. MILLER. 

